Recently, following the proliferation of personal computers, ink-jet recording system printers are rapidly spreading. Specifically, in the field of graphic art and designing requiring its high quality image, its utilization is being taken notice.
As a recording sheet used for ink-jet recording system, conventionally, a recording sheet wherein an ink receiving layer (hereinafter, referred also to as "ink-absorption layer") is provided on ordinary paper or a support referred to as an ink-jet recording paper has been used. However, when the above-mentioned recording papers are employed, much ink blurring results and glossiness is low. Therefore, the above-mentioned recording papers could not be employed for the above-mentioned field wherein high resolution and high glossiness is required.
In addition, when a transparent support is used to produce an original for an OHP (over-head projector), there was the problem that a porous ink-absorption layer interferred light transmittance.
In order to overcome the above-mentioned problems, there is proposed a gelatin containing layer as an ink-absorption layer with high transparency and high ink-receptivity. For example, for a layer with high ink-absorption, the use of gelatin is disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter, referred to as Japanese Patent O.P.I. Publication) No. 59-255131, and an ink receiving layer comprised of gelatin having a specific pH in Japanese Patent O.P.I. Publication No. 62-263084. A combination use of acid processed gelatin and a fluorine-containing surfactant is disclosed in Japanese Patent O.P.I. Publication No. 1-146784. In Japanese Patent O.P.I. Publication No. 6-64306 is proposed a recording sheet obtained by coating a gelatin layer on a support to be in gel state and then drying it by a cold drying method.
As disclosed in the above-mentioned publications, the ink jet recording sheet having an gelatin containing ink receiving layer provided improved ink absorption, however, it has been proved that, when printing is carried out using a high speed printing printer with high resolution capability, the technologies disclosed in these publications can not give high quality printing images due to insufficient ink absorption. It has also been proved that, particularly when printing is carried out under low temperature and high humidity conditions, the degree of swell of gelatin by the ink is reduced and ink absorption is greatly lowered.
It has been found that glossiness at high density image portions or transparency is lowered, when printing according to the technologies described above is carried out using some kinds of ink jet printers and some kinds of inks.
The physical properties of the ink receiving layer containing gelatin greatly varies depending on temperature or humidity. The layer expands or contracts, depending on humidity change, whereby the recording sheet is curled and results in transporting failure. There are also likely to occur problems in that, during storage under high humidity, the gelatin absorbs moisture and the recording sheets stick to each other or ink is transferred to the back of the upper sheet.